It almost seems like some sort of reverse psychology thing… Russia saying "We forbid you to join NATO" is one of few things that would get these countries to join NATO. "Don't tell us what to do!"
What is Putin's play?
He's been very clear: before the second Ukraine invasion he criticised Lenin for allowing the SSRs to exist and for accepting the loss of Imperial Russia by e.g. accepting Finnish independence. His ambition is to restore Russia to (at least) its pre World War I borders, which would involve the obliteration of nations such as Ukraine and Finland.
Up until now he has zero push back on the butcheries in Chechnya, little pushback on previous atrocities in Ukraine or Syria or shooting down civilian airliners, and he no doubt expected the same this time around.
Why it has to be Putin's play? A lot of people seem to take for granted that Putin knows what he is doing and has a long play with an eventual win.
History is full of leaders making terrible mistakes that eventually put the last nail in their coffins, I don't understand why some think that the only possible option is that there must be something that we are missing because Putin is so smart and has so much control that this can't simply be a huge fail on his part